[question]: why does the emission happen after the migration?

[Rignchen]

In the code we can see

      // Perform the migration
      await this.runTransaction(async () => {
        for (const migration of pendingMigrations) {
          try {
            // Apply migration
            await migration.up(this.db, ...args);

            // Record migration
            await this.recordMigration(migration.name, nextBatch);
            appliedMigrations.push(migration.name);
          } catch (err) {
            throw new MigrationExecutionError(`Failed to apply migration "${migration.name}"`, err as Error);
          }
        }
      });

      for (const migrationName of appliedMigrations) {
        this.emit('migration:applied', migrationName, nextBatch);
      }

and

      // Perform the rollback
      await this.runTransaction(async () => {
        for (const row of rows) {
          const migration = this.migrations.find((m) => m.name === row.name);
          if (!migration) {
            throw new MigrationFileError(`Migration "${row.name}" not found.`);
          }

          try {
            // Revert migration
            await migration.down(this.db, ...args);

            // Remove migration record
            await this.removeMigration(migration.name, currentBatch);

            appliedMigrations.push(migration.name);
          } catch (err) {
            throw new MigrationExecutionError(`Failed to rollback migration "${migration.name}"`, err as Error);
          }
        }
      });

      for (const migrationName of appliedMigrations) {
        this.emit('migration:rollback', migrationName, currentBatch);
      }

I personally find that confusing, why do you want for all transactions to be done before emitting that a migration is done? why not

      // Perform the migration
      await this.runTransaction(async () => {
        for (const migration of pendingMigrations) {
          try {
            // Apply migration
            await migration.up(this.db, ...args);

            // Record migration
            await this.recordMigration(migration.name, nextBatch);
            appliedMigrations.push(migration.name);

            // Notify user
            this.emit('migration:applied', migration.name, nextBatch);
          } catch (err) {
            throw new MigrationExecutionError(`Failed to apply migration "${migration.name}"`, err as Error);
          }
        }
      });

and

      // Perform the rollback
      await this.runTransaction(async () => {
        for (const row of rows) {
          const migration = this.migrations.find((m) => m.name === row.name);
          if (!migration) {
            throw new MigrationFileError(`Migration "${row.name}" not found.`);
          }

          try {
            // Revert migration
            await migration.down(this.db, ...args);

            // Remove migration record
            await this.removeMigration(migration.name, currentBatch);

            appliedMigrations.push(migration.name);

            // Notify user
            this.emit('migration:rollback', migration.name, nextBatch);
          } catch (err) {
            throw new MigrationExecutionError(`Failed to rollback migration "${migration.name}"`, err as Error);
          }
        }
      });

I think this would make more sens and I am curious of the reason why you didn't choose to so it like that